Recently, a group of MIT Plasma Science and Fusion Center (PSFC) research scientists figured out how to manipulate or control the anomalous Hall effect and Berry curvature for advanced use in computers, robotics, and sensors. Hang Chi, Yunbo Ou, Jagadeesh Moodera, and co-authors wrote extensively to explore their discovery and share it with the world. 

 

The History of Hall

Let’s start with a little bit of background on Hall. In the late 1800s, Edwin Hall discovered that when he placed a magnet at right angles to a strip of metal with a current running through it that one side had a greater charge than the other. The magnetic field was deflecting the current’s electrons toward the metal. This phenomenon was named in his honor. Since then, we’ve learned about the important role played by quantum mechanics.

 

Link Between Physics and Quantum Mechanics

One article by Electronic Products and Technology suggests we think of classical physics like “a map of Arizona,” and quantum mechanics as “a car trip through the desert.” While the map gives us a macro view, it doesn’t account for the random events a driver could face, like an animal running out into the road. They say, “Quantum spaces, like the journey the driver is on, are governed by a different set of traffic rules.” Ultimately, while the Hall effect is induced by an applied magnetic field in a classical system, in a quantum case, it may occur without the external field, i.e., the anomalous Hall effect.

 

Continuing the same driving-in-the-desert metaphor, the Berry phase — named for British physicist Michael Berry — is like the GPS log of the entire trip. In analyzing the log, you could plot the curvature of the space. This “Berry curvature” can naturally shift electrons, inducing the Hall effect without a magnetic field. 

 

Many have observed the anomalous Hall effect, but none have been able to manipulate it until the MIT scientists created a new method. They grew a thin layer of magnetic material  (chromium telluride) on the base of crystals (aluminum oxide or strontium titanate). When combined, the magnetism and the interface it created with the crystal bases caused layers to stretch or squeeze. In other words, the anomalous Hall effect was manipulated. 

 

Potential Outcomes

Although this breakthrough moment occurred at a molecular level, its potential outcomes will be observable in everyday life. Hard drives, for example, store data in tiny magnetic areas, but if they were created using insight from this MIT discovery, they could store even more data! The same is true for robotics, especially “soft robots” that have flexible components. The “stretchable” magnetic material could be used as sensors to provide better precision feedback. Used to detect small changes in the environment, the material could even be used to create ultra sensitive health monitoring equipment. 

 

Apex Magnets

At Apex Magnets, we sell many different kinds of permanent magnets that can be implemented in the field of electronics. We also offer custom magnets in various shapes, sizes, and strengths. Fill out a custom magnet request form. We’ll review your RFQ within 1-2 business days for FREE with no obligation to purchase. 

 

If you have questions about any of our products, don’t hesitate to call at 1.304.257.1193.